Estimating soil organic carbon content at variable moisture contents using a low-cost spectrometer

Research-grade spectrometers such as ASD are widely used in the lab to estimate soil properties, but they are bulky, heavy, and not easily deployable to measure field soils. The newer FT-NIR spectrometers are compact, lightweight, and robust, suitable for developing portable sensors for emerging applications such as field-based soil carbon stock assessment. In this study, we investigated the usefulness of an FT-NIR spectrometer (NanoQuest) for estimating SOC content while correcting for the effect of soil moisture using External Parameter Orthogonalization (EPO), and its performance was compared to that of ASD. To develop EPO transformation, five levels of soil moisture were used at 0, 0.07, 0.13, 0.18, 0.24, and 0.30 g g−1. We tested two modeling approaches: Partial Least Squares Regression (PLSR) and Support Vector Regression (SVR). The results showed that EPO was more effective in correcting for the moisture effect as samples became drier. ASD gave a better performance in estimating SOC with SVR (R2: 0.17 to 0.84, RMSE: 6.1 to 3.9 g C kg−1, bias: −0.3 to 0.1 g C kg−1) after EPO transformation. NanoQuest gave slightly lower, but still satisfactory performance in SOC estimation (R2: 0.17 to 0.70, RMSE: 9.2 to 5 g C kg−1, bias: −0.3 to 0.1 g C kg−1). EPO substantially reduced the bias of the SOC models for both ASD and NanoQuest. This study demonstrates the usefulness of low-cost FT-NIR spectrometers for SOC measurement at varying moisture contents and their great potential for field-deployable soil sensor development

Plantas com possível atividade hipolipidêmica: uma revisão bibliográfica de livros editados no Brasil entre 1998 e 2008 Plants with possible hypolipidemic activity: a review of books published in Brazil between 1998 and 2008

O objetivo deste trabalho foi realizar levantamento sobre as plantas medicinais indicadas para o tratamento da hiperlipidemia, hipercolesterolemia e/ou aterosclerose. Este estudo foi feito a partir da pesquisa bibliográfica em 32 livros publicados no Brasil entre 1998 e 2008, resultando em lista de 85 espécies distribuídas em 53 famílias, principalmente Asteraceae e Fabaceae, com 54 espécies exóticas e 31 nativas. As espécies mais citadas foram Allium sativum (Alliaceae), Cynara scolymus (Asteraceae), Curcuma longa (Zingiberaceae), Allium cepa (Alliaceae), Echinodorus grandiflorus (Alismataceae), Taraxacum officinale (Asteraceae), Vernonia condensata (Asteraceae), Cuphea carthagenensis (Lythraceae) e Curcuma zedoaria (Zingiberaceae). As espécies nativas, citadas em pelo menos 2 livros, foram investigadas para alguma evidencia científica relacionada a possíveis efeitos hipolipidêmico, hipocolesterolêmico e/ou contra aterosclerose. Somente foram encontrados estudos científicos, relacionados a estes efeitos, para as espécies nativas Cuphea carthagenensis e Echinodorus grandiflorum, indicando a necessidade de pesquisas que possam garantir a segurança e a eficácia do uso destas espécies.<br>The aim of this study was to survey medicinal plants indicated for the treatment of hyperlipidemia, hypercholesterolemia and/or atherosclerosis. This study was performed from a review of 32 books published in Brazil between 1998 and 2008, resulting in a list of 85 species belonging to 53 families, especially Asteraceae and Fabaceae, with 54 exotic and 31 native species. The species most often cited were Allium sativum (Alliaceae), Cynara scolymus (Asteraceae), Curcuma longa (Zingiberaceae), Allium cepa (Alliaceae), Echinodorus grandiflorus (Alismataceae), Taraxacum officinale (Asteraceae), Vernonia condensata (Asteraceae), Cuphea carthagenensis (Lythraceae) and Curcuma zedoaria (Zingiberaceae). Native species cited in at least 2 books were investigated for some scientific evidence related to possible hypolipidemic and hypocholesterolemic effects and/or action against atherosclerosis. Scientific studies related to these effects were found only for the native species Cuphea carthagenensis and Echinodorus grandiflorum, indicating the need for studies capable of assuring the safety and the efficacy as to the use of these species